For unfilled PBT UL-94 (0.8mm) class V0 we recommend the use of either FR-1025 or F-2400, at 8.5-10% Br and 6-7% AO synergist.
For class 5V (3.2mm), FR loading would be similar, but additionally would need a heat sink
material like melamine cyanurate (FR-6120) at a loading of 15-20% and use of anti-dripping agent of the type of PTFE at a loading of 0.5-1.0%.